Field of the Invention
The present invention relates to a multi-layered drink and a method for the manufacture thereof.
Description of Related Art
There is a great interest in offering drinks in an attractive manner as concerns the taste as well as the appearance of them. A drink consisting of several separate layers has a particularly attractive effect thanks to the abundant colors and the various separate layers, as each layer can be drunk separately, or a combination of different layers can be drunk together. Such a product and a simple and fast manufacture of such a product are therefore very interesting for the gastronomy sector.
In general, there are the following possibilities of manufacturing a multi-layered drink:                arrangement in layers due to different densities        arrangement in layers due to different viscosities        arrangement in layers due to a combination of different densities and different viscosities        arrangement in layers due to different states of aggregation (liquid, frozen, frothy)        
Multi-layered drinks that are layered due to different densities are, for example, cocktails. For the manufacture of a multi-layered cocktail, the individual layers have to be combined particularly carefully. In the process, the individual ingredients of the drink are carefully poured in over a spoon, so that they do not intermingle. It is thereby possible to form several layers of different colors. The ingredients used for this are layered according to their density. That means, first, the ingredient having the highest density is filled into the vessel as the lower layer. The further ingredients are each filled in with decreasing density. However, these individual layers are not stable; after some time, they intermingle completely. Moreover, the ingredients are not separated by a clear phase boundary.
Multi-layered soft drinks can also be prepared by building up individual layers of drinks, such as juices. In this case, too, the individual ingredients are selected such that there are several separate layers due to a difference in density. However, they also intermingle after some time.
An arrangement in layers on the basis of different densities is also described in WO 2005/046409. This document discloses a method and a device for the manufacture of multi-layered drinks. Differences in the density of the individual liquid layers permit to prepare a drink exhibiting clearly separated and stable layers. The desired difference in density of the individual layers is achieved by adjusting a drink concentrate to a certain density by adding water. Here, it is necessary for the difference in density between the individual layers to be at least 0.1% to obtain clearly separated layers. However, a slow addition of the individual layers is required to reduce turbulences. To minimize an intermingling of the individual layers due to diffusion or convection of the liquids, a break must be made after one layer has been added. In particular in case of hot drinks, it is additionally necessary to check the temperature of the individual layers. As greater turbulences and an accelerated diffusion occur at higher temperatures, the individual layers have to exhibit a temperature gradient where the lower layer has to be colder than the upper layer. Thus, the described method represents a time consuming and complicated method. In case of fruit juices, it moreover has to be taken into consideration that various fruit juices generally have very similar densities. It is therefore necessary to increase the density by adding a weighting agent, such as sugar.
An arrangement in layers on the basis of different viscosities is described in Research Disclosure 2001, 443, page 388, ID.-No. 443053. Here, a two-layered drink of which the individual layers comprise different viscosities is prepared. Here, the individual layers contain different hydrocolloids in an aqueous solution, e.g. propylene-glycol-alginate and modified starch. In addition, colorants and flavoring agents can be added to individual layers. The individual layers can also be formed again after the drink has been mixed. High viscosity, however, always involves an unpleasant feeling in the consumer's mouth.
An arrangement in layers on the basis of a combination of different densities and viscosities is described in EP-A-1 415 548. Here, a two-phase drink is disclosed, where the lower phase has a density that is higher by at least 0.02 kg/dm3 (20 kg/m3) than that of the upper phase. In addition, one of the phases contains xanthan for modifying the viscosity, and at least one further hydrocolloid is added to the other phase. The hydrocolloids serve as stabilizers to permit a clear separation of the two phases. Here, the individual phases have a difference in density as well as a difference in viscosity to make intermingling difficult. However, in spite of the use of hydrocolloids as stabilizers, it is necessary for the difference in density of the individual phases to be at least 0.02 kg/dm3 (20 kg/m3). If the density of the lower phase is below 1.094 kg/dm3 (1094 kg/m3), and the density of the upper phase is below 1.05 kg/dm3 (1050 kg/m3), clear phase separation is only achieved if the difference in density is at least 0.03 (30 kg/m3) or 0.04 kg/dm3 (40 kg/m3).
An arrangement in layers on the basis of different states of aggregation is known e.g. from coffee drinks that have an upper layer of milk froth. Such a frothy layer, however, is not stable but collapses after some time. Even a frozen layer is not stable as this layer will melt when it is left at room temperature.